1. Fields of the Invention
The present invention relates to a blow gun, and more particularly, to a blow gun having two springs which share the force applied thereto so as to have a long service life.
2. Descriptions of Related Art
The conventional blow gun is disclosed in Taiwan Patent Publication Number 264733 and comprises a body with a first path for introducing air into the body, and a second path for releasing air out from the body. A first hole and a second hole are located between the first and second paths such that a valve unit is pivotably installed thereto. The body has two plates and each plate has a hole. The trigger has two protrusions are pivotably connected to the two holes of the two plates. A stop is located at outside of the body and close to the second path. The first hole includes an inclined portion at the outlet thereof. The trigger has a nose which contacts the outside of the inclined portion. A belly is formed beneath the nose. The nose has a curved portion at the top thereof and a vertical stop portion is located at the distal end of the curved portion. The vertical stop portion is located at the outside of the stop of the body. The valve unit is composed of a spring and a rod, wherein the spring is engaged with the first hole, the rod has an enlarged portion which contacts the spring. The shank of the rod is inserted in the second hole and has two O-rings mounted thereto. The enlarged portion has a semi-circular portion and the shank has a smaller section which has an elongate hole defined therethrough which is located in the first hole. The semi-circular portion contacts the belly of the trigger.
When the user pulls the trigger, the spring is compressed by the enlarged portion of the rod so that the elongate hole, the first path and the second path are in communication with each other. However, there is only one spring in the body of the blow gun, and the spring tends to reach its fatigue point after frequent operations of the trigger. Once the spring fails to response, the blow gun cannot be used.
The present invention intends to provide a blow gun to eliminate the shortcomings mentioned above.